What do the following two equations represent? $2x-2y = -4$ $2x+2y = 2$
Putting the first equation in $y = mx + b$ form gives: $2x-2y = -4$ $-2y = -2x-4$ $y = 1x + 2$ Putting the second equation in $y = mx + b$ form gives: $2x+2y = 2$ $2y = -2x+2$ $y = -1x + 1$ The slopes are negative inverses of each other, so the lines are perpendicular.